Battery Life Calculator
Estimate battery life for Arduino, ESP32, and IoT devices.
85%
Estimated battery life
2.1 days
3000 mAh × 85% eff = 2550 effective mAh ÷ 50 mA
Hours
51.0
Days
2.1
Months
0.1
Years
0.01
Plan your battery-powered project runtime
Select from common batteries (18650, LiPo, AA) and device presets (Arduino, ESP32, nRF52840) to estimate how long your project will run on a single charge.
Frequently asked questions
- How is battery life calculated?
- Battery life = (Battery capacity × efficiency) ÷ average current draw. For example, a 2000mAh battery powering a 50mA device at 85% efficiency = 34 hours.
- Why does efficiency matter?
- Voltage regulators and DC-DC converters are not 100% efficient. A linear regulator stepping down from 5V to 3.3V wastes ~34% as heat. DC-DC converters are typically 80–95% efficient. Always account for this when calculating battery life.
- How do I extend battery life?
- Use deep sleep modes (ESP32 deep sleep: 10µA vs 240mA active), reduce polling frequency, lower transmit power, use efficient regulators, and only power peripherals when needed.
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